Site Class

Ground Profile Name

Average Properties in Top 30 m

Average Properties in Top 30 m

Average Properties in Top 30 m

Average Shear Wave Velocity,  (m/s)

Average Standard Penetration Resistance,

Soil Undrained Shear Strength, su

A

Hard rock(1)(2)

 > 1500

N/A

N/A

B

Rock(1)

760 <  ≤ 1500

N/A

N/A

C

Very dense soil
and soft rock

360 <  < 760

> 50

su > 100 kPa

D

Stiff soil

180 <  < 360

15 ≤ ≤ 50

50 kPa < su ≤ 100 kPa

E

Soft soil

 < 180

< 15

su < 50 kPa

Any profile with more than 3 m of soil with the following characteristics:
• plasticity index: PI > 20
• moisture content w ≥ 40%, and
• undrained shear strength: su < 25 kPa

F

Other soils(3)

Site-specific evaluation required

Column 1

2

3

4

5

Notes to Table 4.1.8.4.A.:
(1)  Site Classes A and B, hard rock and rock, are not to be used if there is more than 3 m of softer materials between the rock and the underside of footing or mat foundations.  The appropriate Site Class for such cases is determined on the basis of the average properties of the total thickness of the softer materials.  (See Appendix A.)
(2)  If  has been measured in-situ, the Fa and Fv values derived from Tables 4.1.8.4.B. and 4.1.8.4.C. may be multiplied by (1500 / )1/2.
(3)  Other soils include:
(a)    liquefiable soils, quick and highly sensitive clays, collapsible weakly cemented soils, and other soils susceptible to
failure or collapse under seismic loading,
(b)    peat and/or highly organic clays greater than 3 m in thickness,
(c)    highly plastic clays (PI > 75) more than 8 m thick, and
(d)    soft to medium stiff clays more than 30 m thick.

 

Type of SFRS

Rd

Ro

Restrictions(2)

Cases Where IEFaSa(0.2)

Cases Where IEFvSa(1.0)

< 0.2

≥ 0.2 to < 0.35

≥ 0.35 to ≤ 0.75

> 0.75

> 0.3

Steel Structures Designed and Detailed According to CSA S16(3)

Ductile moment-resisting frames

5.0

1.5

NL

NL

NL

NL

NL

Moderately ductile moment-resisting frames

3.5

1.5

NL

NL

NL

NL

NL

Limited ductility moment-resisting frames

2.0

1.3

NL

NL

60

30

30

Moderately ductile concentrically braced frames

 

 

 

 

 

 

 

          Tension-compression braces

3.0

1.3

NL

NL

40

40

40

          Tension only braces

3.0

1.3

NL

NL

20

20

20

Limited ductility concentrically braced frames

 

 

 

 

 

 

 

          Tension-compression  braces

2.0

1.3

NL

NL

60

60

60

          Tension only braces

2.0

1.3

NL

NL

40

40

40

Ductile buckling-restrained braced frames

4.0

1.2

NL

NL

40

40

40

Ductile eccentrically braced frames

4.0

1.5

NL

NL

NL

NL

NL

Ductile plate walls

5.0

1.6

NL

NL

NL

NL

NL

Limited ductility plate walls

2.0

1.5

NL

NL

60

60

60

Conventional construction of moment-resisting frames, braced frames or plate walls

 

 

 

 

 

 

 

          Assembly occupancies

1.5

1.3

NL

NL

15

15

15

          Other occupancies

1.5

1.3

NL

NL

60

40

40

Other steel SFRS(s) not defined above

1.0

1.0

15

15

NP

NP

NP

Concrete Structures Designed and Detailed According to CAN/CSA-A23.3

Ductile moment-resisting frames

4.0

1.7

NL

NL

NL

NL

NL

Moderately ductile moment-resisting frames

2.5

1.4

NL

NL

60

40

40

Ductile coupled walls

4.0

1.7

NL

NL

NL

NL

NL

Ductile partially coupled walls

3.5

1.7

NL

NL

NL

NL

NL

Ductile shear walls

3.5

1.6

NL

NL

NL

NL

NL

Moderately ductile shear walls

2.0

1.4

NL

NL

NL

60

60

Conventional construction

 

 

 

 

 

 

 

               Moment-resisting frames

1.5

1.3

NL

NL

15

NP

NP

               Shear walls

1.5

1.3

NL

NL

40

30

30

Other concrete SFRS(s) not listed above

1.0

1.0

15

15

NP

NP

NP

Timber Structures Designed and Detailed According to CSA O86

Shear walls

 

 

 

 

 

 

 

               Nailed shear walls: wood-based panel

3.0

1.7

NL

NL

30

20

20

               Shear walls: wood-based and gypsum panels in combination

2.0

1.7

NL

NL

20

20

20

Column 1

2

3

4

5

6

7

8